Manufacture of manganese dioxide



Patented Jan. 22, 1935 q uNirEosTATEs PATENT OFFICE MANUFACTURE OF MANGANESE DIOXIDE Yogoro Kato, Ebara-Gun, Tokyo-F11, Japan, as-

signor of fifty per cent to Kaoru Oyama, the representative director of Yuasa Storage Battery Company, Ltd., Osaka-Fu, Japan No Drawing. Application February 25, 1929 Serial No. 342,679

1 Claim. (01. 23-145) The invention relates to the manufacture or chemical action is exothermic so that heat reproduction of manganese dioxide (M1102), from quired for the oxidation is much reduced. the lower oxides of manganese. My object is the By my invention manganese dioxide can be successful and inexpensive production of manproduc d from a lower oxide or oxides of man- 5 ganese dioxide, especially for use in dry batgane or om y manganese compound that 5 teri can be converted into the oxide by heat, by heat- The higher oxide of manganese, i. e., maning said oxide or manganese compound in the ganese dioxide, is extensively used in dry batpresence of an alkali to temperatures above 200 teries as a depolarizer and the market demand ThiS temperature s below that at which the for it is very large. Attempts to produce manmanganese dioxide will decompose and above that 10 ganese dioxide by oxidizing lower oxides of manat ch no reaction Will occur. ganese by passing oxygen over the latter have y the term o the P p O y hitherto been unsuccessful. I have discovered v n, 1ud ny l und lu x that any Iower oxide of manganese, whether hydroxides, and carbonates Of alkali, OI alkaline 5 natural or artificial, if heated to moderately high earths, and so y Compounds that y be temperatures in the presence of one or more alkav ed i he e, a y heating- 1i and supplied ith x h th r free By way of illustration, I shall mention three oxygen, or with any gas containing oxygen, such practical examples of the application or practice as air, can very readily and inexpensively be con- Of y inventienverted into manganese dioxide. The alkali acts E'fllample One kilogram of p wd ed 20 a a catalyzer, lower oxide of manganese, or of any powdered By lower oxide of m a ese, I m any naturalorartificialmanganesesubstance that may oxide that contains three or less oxygen atoms be Converted intO Such OXide p heating, add with two manganese atoms, and which is not a thirty grams o Sodium hydroxide 0 y ams depolarizer. By manganese dioxide, I mean the of i m r on nd x h h Pl 25 oxide of tetravalent manganese, which has dethe mixture into a cylindrical container and expolarizing power, and other oxidizing power, and ternally heat the container, electrically or otherto a marked degree. In substances that can be Wise- Rotate the Container While he nd converted i t id f manganese by h ti I introduce therein oxygen, or air for oxidation, for include carbonate, or hydroxide of manganese, One w hours- When Oxidation is terminated, 30 or any other natural or artificial manganese comremove the product and Wash With Water, pound containing Carbonate or hydroxide if necessary, with dilute acid solution.

Natural manganese oxide ores are usually found e the rotating cylindfer in states of varying degree of oxidation, the ratio tammg raw material a alkah, as speclfifedi m of oxygen atoms to one atom of manganese rang- Example Introduce oxygen'conta'lmng 35 ing between one and two. By my invention almost 3235;; i g i gg igfi g g ggf iggag all manganese in these ores can be converted into the contents and wash as in Example No. 1. manganese dloxlde' Example No. 3.Place the raw material and For the successful practice of my invention, it alkali as specified in Example 1 into a 40 is not necessary that either natural or artificial Verbemtory f Agitate the contents and at manganese oxide be pure. The presence of ordithe same time Subject the same to an oxidizing nary impurities such as silica, or iron oxides, etc., fiame w Oxidation is terminated, remove when they are not combined chemically with nd h th d t 4r manganese, does not interfere with oxidation of In all three above examples oxidation comthe manganese into the dioxide. mences at a temperature above 200 C. and is I have found that when steam is added to the most active at or around 500 C. oxygen, oxidation seems to be greatly accelerated. When alkaline earth compounds are used in One outstanding advantage of the oxidizing place of alkalies, they may be removed after oxiprocess in my invention lies in the fact that the dation, by washing with dilute acid. 50

of manganese or any compound of manganese that may be converted into the lower oxide by heating is heated in a dry state, in the presence of substantially 3 to 5% of an alkali metal or alkaline earth metal compound selected from the group consisting of the oxides, hydroxides, carbonates, or compounds convertible by heating into the same, to a temperature of 200 C. or higher, whilst passing over it gas containing free oxygen and thus converting the lower manganese 10 oxide into manganese dioxide.

YOGORO KA'IO. 

